Since February, 1974, we have participated in the SAODAP Cooperative Study of LAAM and Methadone. This application is designed to: (1) Follow 25 patients beyond 40 weeks maintenance on LAAM or Methadone; (2) Induct two additional groups: patients on methadone for 40 weeks may be transferred to LAAM; and, women of non-child bearing potential; (3) Assess additional predictive rating instruments as the MMPI; and, (4) Collect continuing toxicologic data, particularly EKG at 24 weeks. We estimate sustained maintenance for the duration of the study for patients now in the study, as our drop-outs usually occur during the first 20 weeks of treatment.